Windows Phone 7 and OneNote

I'd never used OneNote before I picked up my Windows Phone 7 - but it's extremely handy, even more so than the Notes or Tasks that I'd used for the same purposes on my BlackBerry.  The only downside was that they (still) don't have notifications attached, which means OneNote notebooks aren't a replacement for Outlook Tasks.  That said, the ability to synchonize to the cloud allows better access - from any computer anywhere - rather than just from computers that I have my Outlook client installed on.  In addition, the formatting capabilities of OneNote are very useful compared to Outlook notes or tasks.  I find myself recording more information in my notebooks - because it lends itself to better organization, and it's easier to get at.
What's Possible Now
The Windows Phone how-to pages include information on how to set up a "default" synchronizing notebook called "Personal (Web)" on your SkyDrive.  This (inexplicably) shows up on the phone with a section called "Unfiled Notes" and you're warned against changing it.  This prevents a useful organizational feature of OneNote - the ability to file notes into sections, and even into different notebooks.
If you happen to have an internet-accessible corporate SharePoint 2010 server, you can "keep" a copy of those notebooks on the phone and synchronize them with the server.  I don't have a SharePoint 2010 server architecture lying about, and my organization is probably not looking to spend a ton to get one.  I really wanted to segregate information and realize some of the benefits of multiple sections and notebooks.
Officially, That's It
As far as Microsoft's documentation goes, that's all you can do.  They don't mention anything about using more than one notebook.  In fact, in all the news I've read on the internet about what's coming in a future update (the Mango, 2011H2 update) is "better" Office integration.
So you're stuck, right?
Pushing the Boundaries
It turns out you can put any SkyDrive notebook on the phone - although Microsoft doesn't explain how, or tout this capability.  It's relatively easy to do, but there are limitations, which is why you aren't hearing this from Microsoft.  It's so easy that I didn't realize how seamless it was until I broke it and re-enabled it by accident.
Quite simply, create any OneNote notebook on your SkyDrive, then use the phone's Internet Explorer to navigate to your Live account to find the document in SkyDrive, and open on it.  If you did this on your desktop's IE, it would open in OneNote's WebApp.  But on the phone, it switches immediately to the Office Hub, opening the notebook on the phone, and syncs the sections.
But wait - I said I "broke" this and then fixed it.  How did I do that?  I changed my phone's Internet Explorer settings to look at the pages in "desktop" mode, not mobile.  (Some sites have way too limited "mobile" versions, don't they?)  Seems that if you surf to your OneNote notebook in "desktop" mode, it'll fire up the OneNote WebApp, but if you hit it in "mobile" mode, it knows to download and sync it with the Office Hub.  Who knew?
Getting Rid of "Personal (Web)"
Great!  You can put any OneNote notebook on the phone... so why settle for a hobbled notebook called "Personal (Web)" with an "Unfiled Notes" section that you can't change?
Only one thing - if you create a new note (page), it needs a notebook to get saved in, and that's the "Unfiled Notes" section of the "Personal (Web)" notebook.  Again, the documents don't say this - but you can change that default.  Open the Office Hub and tap the "all" button.  Tap the "notebooks" pivot heading.  Try to tap the garbage can icon, then pick the "Personal (Web)" notebook - the phone will complain, and give you instructions on how to change the default.  Just to save you from having to do that, press "OK" and the back button to get back to the notebook screen, and tap and hold the notebook section (not the notebook) you want to set as the default.
Life Isn't Perfect Yet
But of course, there are some issues.  It seems like the phone reads different "section" information than the WebApp.  When you add any notebook to the phone using what I've described, the first section in the notebook is always "Untitled".  No matter what you do, you can't rename that.  In fact, any section renaming you do on the web using the WebApp doesn't EVER get reflected on the phone.  Moreover, if you try to change page names on the phone, you get a sync error.  You can view the sync errors on the web, but your only option is to copy the data out of the changed page, because the only resolution you have to sync errors is to delete the version the phone made.
It'll Do Until Mango
I could (and will) ask for more, but this will do.  I can now have whatever notebook pages I want on my phone, synced so I can work on them offline, in very high-fidelity. I can structure my notebooks' sections and pages any way I want... as long as I do it right the first time, and delete the automatically added first section.  I can even add voice notes, pictures, and video to the pages from the phone.  On top of that, with a little tap-and-hold, I can pin any notebook page right to the start menu.
Personally, I don't see how the one limitation here - section and page naming and syncing - is taking a year to fix.
Recap
Create your notebook "properly" using the WebApp

1. Create the notebook
2. Add a new section
3. Delete the original "Untitled Section"
4. Construct your notebook sections and pages as you wish - named perfectly on creation.

Link the notebook on the phone

1. Surf in IE "mobile" mode to the SkyDrive
2. Open the notebook

Limitations

• Notebook, section, and page names can NOT be changed.  If you want to rename a section or page, create a new one, move the data in the pages, and delete the original (old) named section/page.

To the cloud!